Method, apparatus and system for determining resource indices

ABSTRACT

The present invention relates to a method, apparatus and system for determining resource indices in a wireless communication system, which explores and implements for at least two control channel elements (CCEs) for a user equipment (UE), maps the CCEs to at least two resource indices for the UE according to a predetermined mapping rule. It can determine multiple resource indices to a UE implicitly according to some embodiments of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application No.PCT/CN2008/072937, filed on Nov. 4, 2008, which is hereby incorporatedby reference in its entirety.

FIELD OF INVENTION

The present invention relates to a wireless communication field,especially relates to a method, apparatus and system for determiningresource indices.

BACKGROUND OF THE INVENTION

It is previously known that to enable coherent demodulation ofacknowledgement (ACK/NACK) signals from multiple users in the uplink ofa communication system, a demodulation reference signal (DRS) isallocated to each of the user equipments (UE). The DRS is taken from aset of orthogonal DRS.

Furthermore, in the downlink, a broadcast channel is used fortransmission of control information to the UEs from a base station. Theinformation in this broadcast channel is composed of multiple segmentsof information, denoted control channel elements (CCE). Each UE isallocated with one or several consecutive CCEs and receives itsdedicated control information, denoted physical downlink control channel(PDCCH) in its allocated CCE segments. The number of allocated CCEs perPDCCH is 1, 2, 4 or 8.

The PDCCH contains information about where and in which format adownlink data burst, denoted physical downlink shared channel (PDSCH),or an uplink data burst, denoted physical uplink shared channel (PUSCH)is transmitted. The UE first finds and reads the PDCCH, then receivesthe PDSCH and decode its message. At a later point in time, the UE sendsan ACK/NACK in response to the received PDSCH message in the uplink tothe base station.

To avoid explicit scheduling of a resource index (DRS indices orACK/NACK indices) to be used for this ACK/NACK message, it is implicitlyindicated from the location of the PDCCH which contained informationabout the decoded PDSCH. More precisely, the location (index) of thefirst CCE in the PDCCH uniquely determines the resource index to be usedfor the uplink ACK/NACK transmission.

SUMMARY OF THE INVENTION

The inventor finds that the conventional art can only assign oneresource index to a UE. But in some situations, the UE needs moreresource indices to transmit uplink data. It is a problem to determinemultiple resource indices for a UE implicitly.

The further problem is how to determine at least two resource indicesfor a UE if the number of available resource indices in each resourceblock (RB) is the same.

The further problem is how to determine at least two resource indicesfor a UE if the number of available resource indices in the first RB isless than the number of available resource indices in other RBs.

The further problem is how to determine at least two resource indicesfor a UE if the number of available resource indices in each RB isdifferent.

The further problem is how to operate if the number of resource indicesfor a UE exceeds the number of available resource indices in one RB.

The further problem is how to allocate the determined DRS indices to themultiple logical antennas of the UE.

The further problem is how to allocate the at least two determinedACK/NACK indices to one logical antenna of the UE.

With a purpose of solving one or more of the above indicated problems,and from the standpoint of the above indicated field of invention, thepresent invention teaches that:

One embodiment of the present invention provides a method fordetermining a resource index in a wireless communication system,including:

for at least two CCEs for a UE, mapping the CCEs to at least tworesource indices for the UE according to a predetermined mapping rule.

For further development, the method further includes establishing the atleast two CCEs for the UE.

Furthermore, the mapping of the CCEs to at least two resource indicesfor the UE according to a predetermined mapping rule includes:

determining at least two resource indices for the UE, wherein eachresource index is determined according to

mod(s+m,K)+a

where s is the first CCE index of the UE, m is an offset, where m≧0, Kis the number of available resource indices within one resource block(RB), and a is a value between 0 and N−1, where N is the number of CCEsfor the UE.

Furthermore, the mapping of the CCEs to at least two resource indicesfor the UE according to a predetermined mapping rule includes:

determining at least two resource indices for the UE, wherein eachresource index is determined according to

$\quad\{ \begin{matrix}{s + m + a} & {{{{if}\mspace{14mu} s} + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {{{{if}\mspace{14mu} s} + m} \geq K^{re}}\end{matrix} $

where s is the first CCE index of the UE, m is an offset, where m≧0, ais a value between 0 and N−1, where N is the number of CCEs for the UE,IC is the number of available resources indices in the first RB, and Kis the number of available resources indices within a second RB.

Furthermore, the mapping of the CCEs to at least two resource indicesfor the UE according to a predetermined mapping rule includes:

determining at least two resource indices for the UE, wherein eachresource index is determined according to

${s + m - {\sum\limits_{m = 0}^{n - 1}\; K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$

where s is the first CCE index of the UE, m is an offset, where m≧0, andK^(m) is the number of available resource indices in the RB_(m), wherem=0, 1, . . . M−1, where M is the number of available RBs for resourceindices, a is a value between 0 and N−1, where N is the number of CCEsfor the UE, and n is the RB index for the UE.

For further development, in response to at least one of the determinedresource indices for the UE exceeds the number of available resourceindices in one RB, the method further includes:

removing the at least one of the determined resource indices; or

rearranging the position of the CCEs that will be received by the UE tomake sure that the resource indices for the UE are in one RB.

Furthermore, the resource indices are DRS indices or ACK/NACK indices.

For further development, the UE has multiple logical antennas, themethod further includes: allocating, by the UE, one determined DRS indexfor each logical antenna.

Furthermore, the method further includes:

allocating at least two determined ACK/NACK indices for one logicalantenna.

Furthermore, wherein the method further includes:

allocating at least one determined ACK/NACK index for one logicalantenna.

One embodiment of the present invention provides an apparatus fordetermining a resource index in a wireless communication system,including:

a mapping unit, configured to map at least two CCEs for a UE to at leasttwo resource indices for the UE according to a predetermined mappingrule.

Furthermore, the apparatus includes:

an establishing unit, configured to establishing the at least two CCEsfor the UE.

Furthermore, the mapping unit includes:

a first determining unit, configured to determine at least two resourceindices for the UE, wherein each resource index is determined accordingto

mod(s+m,K)+a

where s is the first CCE index of the UE, m is an offset, where m≧0, Kis the number of available resource indices within one resource block(RB), and a is a value between 0 and N−1, where N is the number of CCEsfor the UE.

Furthermore, the mapping unit includes:

a second determining unit, configured to determine at least two resourceindices for the UE, wherein each resource index is determined accordingto

$\quad\{ \begin{matrix}{s + m + a} & {{{{if}\mspace{14mu} s} + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {{{{if}\mspace{14mu} s} + m} \geq K^{re}}\end{matrix} $

where s is the first CCE index of the UE, m is an offset, where m≧0, ais a value between 0 and N−1, where N is the number of CCEs for the UE,K^(re) is the number of available resources indices in the first RB, andK is the number of available resources indices within a second RB.

Furthermore, the mapping unit includes:

a third determining unit, configured to determine at least two resourceindices for the UE, wherein each resource index is determined accordingto

${s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$

where s is the first CCE index of the UE, m is an offset, where m≧0, andK^(m) is the number of available resource indices in the RB_(m), wherem=0, 1, . . . M−1, where M is the number of available RBs for recourseindices, a is a value between 0 and N−1, where N is the number of CCEsfor the UE, and n is the RB index for the UE.

For further development, in response to at least one of the determinedresource indices for the UE exceeds the number of available resourceindices in one RB, the apparatus further includes:

a removing unit, configured to remove the at least one of the determinedresource indices; and/or

a rearranging unit, configured to rearrange the position of the CCEsthat will be received by the UE to make sure that the resource indicesfor the UE are in one RB.

Furthermore, the resource indices are DRS indices or ACK/NACK indices.

Further, if the UE has multiple logical antennas, the apparatus furtherincludes:

a first allocating unit, configured to allocate one determined DRS indexfor each logical antenna.

Furthermore, the apparatus further includes:

a second allocating unit, configured to allocate at least two determinedACK/NACK indices for one logical antenna.

Furthermore, the apparatus further includes:

a third allocating unit, configured to allocate at least one determinedACK/NACK index for one logical antenna.

One embodiment of the present invention provides a system fordetermining a resource index in a wireless communication system,includeing:

a base station, configured to communicate to a UE; wherein

the base station is configured to allocate at least two CCEs to the UE;map the CCEs to at least two resource indices for the UE according to apredetermined mapping rule, and send the CCEs to the UE; and

the UE is configured to receive the CCEs from the base station, and mapthe CCEs to at least two resource indices for the UE according to apredetermined mapping rule.

One embodiment of the present invention provides a computer programproduct comprising computer program code, which when executed, enables acomputer to perform the steps of above methods.

Furthermore, the computer program code, when executed, enables acomputer to perform the steps of a user equipment in above methods.

Furthermore, the computer program code, when executed, enables acomputer to perform the steps of a base station in above methods.

One embodiment of the present invention provides a computer readablemedium, wherein the above computer program code is carried by thecomputer readable medium.

The advantages of a method, apparatus and system according to someembodiments of the present invention are that it can determine multipleresource indices to a UE implicitly via mapping the CCEs to at least tworesource indices for the UE according to predetermined mapping rule.

The further advantage according to one embodiment is that it candetermine at least two resource indices for a UE if the number ofavailable resource indices in each RB is the same.

The further advantage according to one embodiment is that it candetermine at least two resource indices for a UE if the number ofavailable resource indices in the first RB is less than the number ofavailable resource indices in other RBs.

The further advantage according to one embodiment is that it candetermine at least two resource indices for a UE if the number ofavailable resource indices in each RB is different.

The further advantage according to one embodiment is that it can avoidsome unavailable resource indices for a UE which exceeds the number ofavailable resource indices in one RB.

The further advantage according to one embodiment is that afterallocating one DRS index to each logical antenna, the UE with multiplelogical antennas can transmit uplink data via different logical antenna.This will improve the uplink performance of a UE through transmitdiversity especially when it is a cell edge UE.

The further advantage according to one embodiment is that afterallocating at least two ACK/NACK indices for one logical antenna, the UEcan transmit uplink data through code or spatial multiplexing via thelogical antenna. This will increase the uplink information transmissioncapacity through code or spatial multiplexing.

BRIEF DESCRIPTION OF THE DRAWINGS

Some methods, a apparatus, and system according to the present inventionwill now be described in detail with reference to the accompanyingdrawings, in which:

FIG. 1 is a schematic and simplified illustration of a multiplexingstructure of DRS and ACK/NACK in one RB;

FIG. 2 is a block diagram of one embodiment of the present invention;

FIG. 3 is a schematic diagram of CCEs structure of an example;

FIG. 4 is a schematic diagram of another CCEs structure of an example;

FIG. 5 is a block diagram of one embodiment of the present invention;

FIG. 6 is a schematic diagram of CCEs structure of an example;

FIG. 7 is a block diagram of one embodiment of the present invention;

FIG. 8 is an architecture diagram of an apparatus of one embodiment ofthe present invention;

FIG. 9 is an architecture diagram of a system of one embodiment of thepresent invention;

FIG. 10 is an architecture diagram of a UE of one embodiment of thepresent invention;

FIG. 11 is an architecture diagram of a base station of one embodimentof the present invention;

FIG. 12 is a schematic diagram of the mapping of CCEs to PDCCH of onedetailed embodiment of the present invention;

FIG. 13 is a schematic diagram of the mapping of CCEs to PDCCH ofanother detailed embodiment of the present invention;

FIG. 14 is a schematic diagram of the mapping of CCEs to PDCCH beforerearranging of one detailed embodiment of the present invention;

FIG. 15 is a schematic diagram of the mapping of CCEs to PDCCH afterrearranging of one detailed embodiment of the present invention; and

FIG. 16 is a schematic and very simplified illustration of a compactdisc carrying computer program code according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In order to give a understanding of the present invention it is firstlydescribed how a UE can transmit uplink information using the followingdata structure.

When a UE transmits uplink control information to a base station, theuplink control information will be confined to one RB which may contain12 sub-carriers and 6 or 7 symbols depending on a cyclic prefix (CP)size. Without loss of generality, we will assume that there are 7symbols per RB in the following description. The uplink controlinformation may be physical uplink control channel (PUCCH). For example,the acknowledgment (ACK/NACK) in response to downlink packettransmission is transmitted on the PUCCH.

In the RB for uplink information transmission, three symbols are usedfor DRS transmission, and the remaining four symbols are used for uplinkinformation transmission. The uplink information may be ACK/NACK orscheduling request. Without loss of generality, this embodiment takesACK/NACK for an example to describe the RB structure. The multiplexingstructure of DRS and ACK/NACK in one RB is illustrated in FIG. 1.

In each time slot of transmitting ACK/NACK on PUCCH, a UE will use oneDRS from a set of available DRSs to enable the use of coherent detectionof the information in the base station.

A sequence with length 12 is used to transmit ACK/NACK or DRS in eachsymbol. Given a base sequence of length 12, a set of 12 sequences aregenerated. These are obtained by multiplication with a linear phase withslope 2πa/12 as follows

r^(a)(n)=e ^(j2πna/12) r(n),n=0,1, . . . ,11;a=0,1, . . . ,11  (1)

where r(n) is the base sequence with length 12, and r^(a)(n) is themodified base sequence. The linear phase shift operations in formula (1)are performed in frequency domain and a linear phase shift in frequencydomain corresponds to a cyclic shift in time domain. Therefore, the 12frequency domain sequences in formula (1) correspond to 12 differentcyclic shifts of the base sequence in the time domain. These 12sequences are orthogonal in the time domain due to this particularchoice of the linear phase shift slopes 2πa/12.

If each UE uses a cyclic shift (or equivalently a phase slope 2πa/12)for its DRS, and different UEs are assigned DRS through the cyclicshifts, in this way it means that if there is a single symbol used forDRS, there are at most 12 UEs multiplexing together per RB. However,there are three symbols available for DRS in the ACK/NACK structure. Inorder to further improve UE multiplexing capacity, code covering in thetime domain is used. Three orthogonal sequences (OS) of length 3 areused for DRS. The three orthogonal sequences (OS) for DRS are shown inTable 1.

TABLE 1 OS Sequence index OS [w(0) w(1) w(2)] 0 [1 1 1] 1 [1 e^(j2π/3)e^(j4π/3)] 2 [1 e^(j4π/3) e^(j2π/3)]

According to the above structure, it can be observed that at mostK=12*3=36 DRS that are orthogonal in time-frequency domain could besupported. If one DRS is allocated for each UE, up to 36 UEs will besupported in one RB.

The 36 DRS are numbered as k=0, 1, . . . 35. The index of DRS is relatedto the cyclic shift and OS. For example, the relation between the DRSindex and the cyclic shift and OS is illustrated in Table 2.

TABLE 2 Cyclic shift index OS_(index) = 0 OS_(index) = 1 OS_(index) = 20 k = 0 12 24 1 1 13 25 2 2 14 26 3 3 15 27 4 4 16 28 5 5 17 29 6 6 1830 7 7 19 31 8 8 20 32 9 9 21 33 10 10 22 34 11 11 23 35

Furthermore, Δ_(shift) is defined as the cyclic shift difference betweentwo adjacent DRS using the same OS, and it can be decided to bedifferent from one, considering multipath delay spreads for the givencell deployment. In the embodiment, three candidate values {1, 2, 3} forΔ_(shift) are used which is configured by base station through higherlayer signalling. For example, if Δ_(shift)=2, then there are only 18DRS available.

If the CCE index is larger than the number K of available DRS in one RB,a second RB is allocated for PUCCH transmission and the DRS allocationcontinues but the PUCCH transmission is now using this second RB. Theabove is only the illustration of DRS resources in one RB, and it ispossible to there are several RBs allocated for PUCCH. These RBs forPUCCH would have the same kind of DRS resources. So in this case, if aUE wants to transmit uplink information to a base station, it has toknow the corresponding RB index, i.e., which RB to transmit the uplinkinformation of the UE, the DRS index, and ACK/NACK indices implicitlyallocated by the base station. After getting the DRS index, thecorresponding cyclic shift and OS would be obtained according to Table2.

Even though a UE has to get the RB index, DRS index and ACK/NACK indiceswhen it transmit uplink information, the determining process of theindex, DRS index and ACK/NACK indices is separate and independent toeach other.

One embodiment of the present invention will now be described withreference to FIG. 2 showing a method for determining a resource index ina wireless communication system. This method may be performed by a UE ora base station.

Block 201, a UE or a base station may establish at least two CCEs for aUE.

When this method is performed by a UE, the block 101 is: the UE receivesat least two CCEs of the UE from a downlink control channel.

When this method is performed by a base station, the block 101 is: thebase station allocates at least two CCEs to the UE.

Block 202, maps the CCEs to at least two resource indices for the UEaccording to a predetermined mapping rule.

Concretely, block 202 may include the following situations.

A. If the number of available resource indices in each RB is the same,determines at least two resource indices for the UE, and each resourceindex is determined according to the following formula (2).

mod(s+m,K)+a  (2)

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the following formula (3).

$\begin{matrix}{{RB} = \lceil \frac{s + m}{K} \rceil} & (3)\end{matrix}$

where s is the first CCE index of the UE, m is an offset, where m≧0, Kis the number of available resource indices within one RB, and a is avalue between 0 and N−1 and may corresponding to the ath CCE of this UE,where N is the number of CCEs for the UE. How to decide a is predefinedrule between the base station and the UE.

The value of K varies with the step size Δ_(shift) and CP size accordingto

$\begin{matrix}{{K = \frac{12*c}{\Delta_{shift}}}{c = \{ \begin{matrix}3 & {{normal}\mspace{14mu} C\; P} \\2 & {{extended}\mspace{14mu} C\; P}\end{matrix} }} & (4)\end{matrix}$

Where Δ_(shift)ε{1,2,3}, and c is the number of OS. Generally speaking,if one RB has 7 symbols, the c=3, and if the RB only has 6 symbols, thec=2.

B. If the number of available resource indices in the first RB is lessthan the number of available resource indices in a second RB, determinesat least two resource indices for the UE, and each resource index isdetermined according to the following formula (5).

$\begin{matrix}\{ \begin{matrix}{s + m + a} & {if} & {{s + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {if} & {{s + m} \geq K^{re}}\end{matrix}  & (5)\end{matrix}$

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the following formula (6).

$\begin{matrix}{{RB} = \{ \begin{matrix}1 & {if} & {{s + m} < K^{re}} \\{\lceil \frac{s + m - K^{re}}{K} \rceil + 1} & {if} & {{s + m} \geq K^{re}}\end{matrix} } & (6)\end{matrix}$

where s is the first CCE index of the UE, m is an offset, where m≧0, ais a value between 0 and N−1 and may corresponding to the ath CCE ofthis UE, where N is the number of CCEs for the UE, K^(re) is the numberof available resources indices in the first RB, and K is the number ofavailable resources indices within a second RB. Here the second RB has ageneral meaning of the other RB except the first RB in the uplinkchannel.

Sometimes, one of the several RBs allocated for uplink informationtransmission has only K^(re) resource indices reserved for its use,where the number of available resource indices K^(re) is less than K.

C. If the number of available resource indices in each RB is different,where the number of available resource indices within RB_(m) is K^(m),where m=0, 1 . . . M−1, determines the RB index for the UE according tothe following formula (7).

$\begin{matrix}{{{RB} = n},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}} & (7)\end{matrix}$

Determines at least two resource indices for the UE, and each resourceindices is determined according to the following formula (8),

$\begin{matrix}{{s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}} & (8)\end{matrix}$

where s is the first CCE index of the UE, m is an offset, where m≧0, andK^(m) is the number of available resource indices in the RB_(m), wherem=0, 1, . . . M−1, where M is the number of available RBs for resourceindices transmission, a is a value between 0 and N−1 and may correspondto the ath CCE of this UE, where N is the number of CCEs for the UE, andn is the RB index for the UE.

For the above situations, if N CCEs are established for the UE, therewill also be maximum N resource indices available for the UE. Whendetermining the at least two resource indices for the UE from the CCEindices, it is very flexible to get the DRS indices. The base station orthe UE can only maps a part of the CCE indices of the UE to the resourceindices or maps the all CCE indices of the UE to the resource indices;when mapping a part of the CCE indices of the UE to the resourceindices, the base station or the UE may map a discretionary CCE index ofthe UE to a resource index. For example, 4 CCEs with indices 4, 5, 6, 7are established for a UE, but it only maps the CCE indices 4, 7 toresource indices for the UE. Anyway, the mapping rule from the CCEindices to resource indices are predefined, i.e., both base station andUE can identify this rule. A set of the resource indices of a UE may benoted as Z.

Usually the elements of Z are less than the number of available resourceindices in one RB, i.e. the allocated resource for one UE is in the sameRB.

However, there exists a special case, where one or more element(s) inthe resource indices for a UE, for example, the largest element, exceedsthe number of available resource indices within one RB and therefore thedetermined resource indices for the UE will be mapped to different RBs.If the resource indices in one RB are numbered from 0, the exceeds meansthat one or more element(s) in the resource indices for a UE is largerthan or equal to the number of available resource indices in one RB; ifthe resource indices in one RB are numbered from 1, the exceeds meansthat one or more element(s) in the resource indices for a UE is largerthan the number of available resource indices in one RB. Since theuplink information must be confined to a single RB for satisfying thetransmission restriction, and the allocated resource indices are validfor one RB only, this event is not allowed. However, the special casecan be avoided by either of the following two solutions.

Exception Solution 1: if at least one of the determined resource indicesfor the UE exceeds the number of available resource indices in one RB,removes the at least one of the determined resource indices. In thiscase, fewer than N DRS s are obtained for the UE.

Exception Solution 2: proper assignment of the CCEs of the downlinkinformation in the downlink to avoid the problem.

If at least one of the determined resource indices for the UE exceedsthe number of available resource indices in one RB, the base stationrearranges the position of the CCEs that will be received by the UE tomake sure that the resource indices for the UE are in one RB. Then theRB index for the UE will be changed to the one that the current resourceindices for the UE belonged to.

It is noted that the index of the first CCE of each UE should be aninteger times of the number of CCEs (1, 2, 4 or 8) in the PDCCHtransmitted to the UE.

As show in FIG. 3, an example with 31 CCEs where the arrows indicateallowed starting positions for PDCCH consisting of four CCEs. Each RBcan hold at maximum 18 CCE in this example.

For example, assume that the downlink control channels consists of anumber of PDCCHs is divided into a total of 31 CCE's and that each RBcan have maximum 18 resource index. Then CCE index 1-18 is mapped to RB1and index 19-31 is mapped to RB2. See FIG. 3. For PDCCHs consisting of 4CCEs, the allowed starting positions are those CCEs with indices 1, 5,9, 13, 17, 21, 25 and 29 and they are indicated in FIG. 3 with arrows.Assume that a UE is allocated the PDCCH with starting CCE index 17. Thecorresponding four resource indices will then belong to both RB1 andRB2, as shown as CCEs marked with grey shade in FIG. 3. Since theresource index shall point out a single RB, the set of resource indicesin FIG. 3 is not allowed. Instead, the base station may arrange theallocation of the PDCCH consisting of 4 CCEs to this UE as shown in FIG.4.

The resource indices may be DRS indices or ACK/NACK indices. Asdescribed above, the mapping process of RB index, DRS indices andACK/NACK indices is separate and independent to each other.

Sometimes, indices hopping are used in the cell to randomize theinter-cell or intra-cell interference. The indices hopping mean that theindices will change with the time according to a certain hoppingpattern. Therefore, after determining the above resource indices (RBindex or ACK/NACK indices or DRS indices), it may further obtain thefinial resource indices according to the predefined hopping pattern.

The UE may use the resource indices to transmit the uplink information.It may include the following situations.

A. The UE with multiple logical antennas, allocates one determined DRSindex for each logical antenna.

A logical antenna is defined as a linear combination of the physicalantenna(s) to transmit data. If some physical antennas do not have DRSindex, they can not be called as logical antenna. Whatever istransmitted from the logical antenna will undergo the defined mappingand be transmitted from the physical antenna(s). In this way, thereceiver will see the physical antenna(s) as an equivalent singletransmit antenna, or logical antenna. Actually, with this arrangement,the receiver becomes agnostic to the number of physical antennas. Theconcept of logical antenna can be extended to multiple logical antennasand each logical antenna is then associated with a unique DRS.

In this case, because at least two different logical antennas have adifferent determined DRS index, the UE can transmit uplink informationvia different logical antenna. This will improve the uplink performanceof a UE through transmit diversity especially when it is a cell edge UE.

Furthermore, the UE may allocate at least one determined ACK/NACK indexfor one logical antenna.

B. The UE with one or more logical antennas allocates at least twodetermined ACK/NACK indices for one logical antenna.

In this case, because one logical antenna has at least two determinedACK/NACK indices, the UE can transmit uplink data through code orspatial multiplexing via the logical antenna. This may increase theuplink information transmission capacity through code or spatialmultiplexing,

Furthermore, The UE may allocate at least one determined DRS index forone logical antenna.

In the prior art, only one resource index can be assigned for a UE.According to the embodiment of the present invention we can see that itcan determine multiple resource indices for a UE implicitly because itmaps the CCEs to at least two resource indices for the UE according topredetermined mapping rule. It can determine at least two resourceindices for a UE if the number of available resource indices in each RBis the same, or if the number of available resource indices in the firstRB is less than the number of available resource indices in other RBs,or if the number of available resource indices in each RB is different.It can avoid some unavailable resource indices for a UE which exceedsthe number of available resource indices in one RB. After allocating oneDRS index to each logical antenna, the UE with multiple logical antennascan transmit uplink data via different logical antenna. This willimprove the uplink performance of a UE through transmit diversityespecially when it is a cell edge UE. Furthermore, after allocating atleast two ACK/NACK indices for one logical antenna, the UE can transmituplink data through code or spatial multiplexing via the logicalantenna. This will increase the uplink information transmission capacitythrough code or spatial multiplexing.

One embodiment of the present invention will now be described withreference to FIG. 5 showing a method for a UE to determine a resourceindex in a wireless communication system.

Block 501, the UE receives its at least two CCEs from a control channel.

The UE may receive a plurality of CCEs as showed in FIG. 6, and the UEwill pick up its CCEs according to its identification.

Block 502, the UE maps its CCEs to at least two resource indicesaccording to a predetermined mapping rule.

Before mapping, the UE may find the CCE indices according to thepositions of its CCEs in a CCE sequence received from the controlchannel.

Referring to the example in FIG. 3, UE 1 will find its CCE index 0. UE 4will find its CCE indices {4, 5}.

In this case, the UE maps its CCE indices to at least two resourceindices according to a predetermined mapping rule. Concretely, it mayinclude the following situations.

A. If the number of available resource indices in each RB is the same,determines at least two resource indices for the UE, and each resourceindex is determined according to the formula (2).

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the formula (3).

B. If the number of available resource indices in the first RB is lessthan the number of available resource indices in a second RB, determinesat least two resource indices for the UE, and each resource index isdetermined according to the formula (5).

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the formula (6).

Sometimes, one of the several RBs allocated for uplink informationtransmission has only K^(re) resource indices reserved for its use,where the number of available resource indices K^(re) is less than K.

C. If the number of available resource indices in each RB is different,where the number of available resource indices within RB_(m) is K^(m),where m=0, 1 . . . M−1, determines the RB index for the UE according tothe formula (7).

Determines at least two resource indices for the UE, and each resourceindices is determined according to the following formula (8).

For the above situations, if the UE receives N CCE indices allocated bythe base station, there will also be maximum N resource indicesavailable for the UE. When the UE maps the at least two resource indicesfrom its CCE indices, it is very flexible to get the resource indices.The UE can only maps a part of its CCE indices to the resource indicesor maps the all its CCE indices to the resource indices; when mapping apart of its CCE indices to the resource indices, the UE may map adiscretionary CCE index of the UE to a resource index. For example, theUE receives 4 CCE indices 4, 5, 6, 7, but it only maps the CCE indices4, 7 to its resource indices. Anyway, the mapping rule from the CCEindices to resource indices are predefined, i.e., both base station andUE can identify this rule.

If at least one of the determined resource indices for the UE exceedsthe number of available resource indices in one RB, the UE removes theat least one of the determined resource indices. In this case, fewerthan N DRSs are obtained for the UE.

The resource indices may be DRS indices or ACK/NACK indices. The mappingprocess of RB index, DRS indices and ACK/NACK indices is separate andindependent to each other.

Sometimes, indices hopping are used in the cell to randomize theinter-cell or intra-cell interference. The indices hopping mean that theindices will change with the time according to a certain hoppingpattern. Therefore, after determining the above resource indices (RBindex or ACK/NACK indices or DRS indices), it may further obtain thefinial resource indices according to the predefined hopping pattern.

Block 503, after determining its resource indices, the UE may use theresource indices to transmit the uplink information. It may includes thefollowing situations.

A. The UE has multiple logical antennas allocates one determined DRSindex for each logical antenna.

In this case, because at least two different logical antennas have adifferent determined DRS index, the UE can transmit uplink informationvia different logical antenna. This will improve the uplink performanceof a UE through transmit diversity especially when it is a cell edge UE.

Furthermore, the UE may allocate at least one determined ACK/NACK indexfor one logical antenna.

B. The UE with one or more logical antennas allocates at least twodetermined ACK/NACK indices for one logical antenna.

In this case, because one logical antenna has at least two determinedACK/NACK indices, the UE can transmit uplink data through code orspatial multiplexing via the logical antenna. This may increase theuplink information transmission capacity through code or spatialmultiplexing,

Furthermore, The UE may allocate at least one determined DRS index forone logical antenna.

In the prior art, only one resource index can be assigned for a UE.According to the embodiment of the present invention we can see that theUE can determine multiple resource indices for a UE implicitly becauseit maps the CCEs to at least two resource indices for the UE accordingto predetermined mapping rule. In this way, the UE uniquely knows whichuplink RB, DRSs and ACK/NACK indices to use when transmitting the PUCCH.The UE can determine at least two resource indices for a UE if thenumber of available resource indices in each RB is the same, or if thenumber of available resource indices in the first RB is less than thenumber of available resource indices in other RBs, or if the number ofavailable resource indices in each RB is different. The UE can avoidsome unavailable resource indices for a UE which exceeds the number ofavailable resource indices in one RB. After allocating one DRS index toeach logical antenna, the UE with multiple logical antennas can transmituplink data via different logical antenna. This will improve the uplinkperformance of a UE through transmit diversity especially when it is acell edge UE. Furthermore, after allocating at least two ACK/NACKindices for one logical antenna, the UE can transmit uplink data throughcode or spatial multiplexing via the logical antenna. This will increasethe uplink information transmission capacity through code or spatialmultiplexing.

One embodiment of the present invention will now be described withreference to FIG. 7 showing a method for a base station to determine aresource index in a wireless communication system.

Block 701, the base station allocates at least two CCEs to a UE.

The base station may schedule a UE by allocating a particular number ofCCEs in relation to Channel Quality Information and amount of controlinformation to be transmitted in downlink direction for the UE. Forinstance, a UE experiencing a low signal to noise ratio (SNR) will beallocated a larger number of CCEs than a high SNR UE since it then canutilize a channel code with a lower code rate to protect the informationbits.

Block 702, the base station maps the CCEs to at least two resourceindices for the UE according to a predetermined mapping rule.

Concretely, it may include the following situations.

A. If the number of available resource indices in each RB is the same,determines at least two resource indices for the UE, and each resourceindex is determined according to the formula (2).

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the formula (3).

B. If the number of available resource indices in the first RB is lessthan the number of available resource indices in a second RB, determinesat least two resource indices for the UE, and each resource index isdetermined according to the formula (5).

Furthermore, the UE or the base station can also determine the RB indexfor the UE according to the formula (6).

Sometimes, one of the several RBs allocated for uplink informationtransmission has only K^(re) resource indices reserved for its use,where the number of available resource indices K^(re) is less than K.

C. If the number of available resource indices in each RB is different,where the number of available resource indices within RB_(m) is K^(m),where m=0, 1 . . . M−1, determines the RB index for the UE according tothe formula (7).

Determines at least two resource indices for the UE, and each resourceindices is determined according to the following formula (8),

For the above situations, if the base station allocates N CCE indicesfor the UE, there will also be maximum N resource indices available forthe UE. When the base station maps the at least two resource indices forthe UE from the CCE indices, it is very flexible to get the resourceindices. The base station can only maps a part of the CCE indices of theUE to the resource indices or maps the all CCE indices of the UE to theresource indices; when mapping a part of the CCE indices of the UE tothe resource indices, the base station may map a discretionary CCE indexof the UE to a resource index. For example, the base station allocates 4CCE indices 4, 5, 6, 7 for a UE, but it only maps the CCE indices 4, 7to resource indices for the UE. If at least one of the determinedresource indices for the UE exceeds the number of available resourceindices in one RB, the base station may remove the at least one of thedetermined resource indices. In this case, fewer than N DRSs areobtained for the UE. In other way, the base station may rearrange theposition of the CCEs that will be received by the UE to make sure thatthe resource indices for the UE are in one RB. Then the base station maychange the RB index for the UE to the one that the current resourceindices for the UE belonged to.

The resource indices may be DRS indices or ACK/NACK indices. Asdescribed above, the mapping process of RB index, DRS indices andACK/NACK indices is separate and independent to each other.

After the base station maps the CCE indices to at least two resourceindices for the UE, it may record the RB index and DRS indices andACK/NACK indices for the UE.

Block 703, the base station may send the CCEs to the UE via a downlinkcontrol channel.

In the base station to UE transmission, i.e. downlink, a number ofcontrol channels, denoted PDCCH, each intended for a particular UE, istransmitted. Each PDCCH consists of 1, 2, 4 or 8 CCE. An example of themapping of PDCCH to CCEs is given in FIG. 6 where four UEs are assumedand UE 1 and UE 2 use a single CCE each and UE 3 and UE 4 use two CCEeach.

According to the embodiment of the present invention we can see that thebase station can determine multiple resource indices for a UE implicitlybecause it maps the CCEs to at least two resource indices for the UEaccording to predetermined mapping rule. So the base station uniquelyknows which RB, DRSs and ACK/NACK indices are allocated to each UE andwhich RB, DRSs and ACK/NACK indices to assume when demodulating thePUCCH from each UE. The base station can determine at least two resourceindices for a UE if the number of available resource indices in each RBis the same, or if the number of available resource indices in the firstRB is less than the number of available resource indices in other RB, orif the number of available resource indices in each RB is different. Thebase station can avoid some unavailable resource indices for a UE whichexceeds the number of available resource indices in one RB.

One embodiment of the present invention will now be described withreference to FIG. 8 showing an apparatus 80 for determining a resourceindex in a wireless communication system, which includes a mapping unit801.

The mapping unit 801 is configured to map at least two CCEs for a UE toat least two resource indices for the UE according to a predeterminedmapping rule.

The apparatus 80 may further include an establishing unit 802 configuredto establishing the at least two CCEs for the UE.

The mapping unit 801 may further include at least one following unit: afirst determining unit 8011, a second determining unit 8012, and a thirddetermining unit 8013.

The first determining unit 8011 is configured to determine at least tworesource indices for the UE, and each resource index is determinedaccording to

mod(s+m,K)+a

where s is the first CCE index of the UE, m is an offset, where m≧0, Kis the number of available resource indices within one RB, and a is avalue between 0 and N−1, where N is the number of CCEs for the UE.

The second determining unit 8012 is configured to determine at least tworesource indices for the UE, and each resource index is determinedaccording to

$\{ {\begin{matrix}{s + m + a} & {if} & {{s + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {if} & {{s + m} \geq K^{re}}\end{matrix}\quad} $

where s is the first CCE index of the UE, m is an offset, where m≧0, ais a value between 0 and N−1, where N is the number of CCEs for the UE,K^(re) is the number of available resources indices in the first RB, andK is the number of available resources indices within a second RB.

The third determining unit 8013, configured to determine at least tworesource indices for the UE, and each resource index is determinedaccording to

${s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$

where s is the first CCE index of the UE, m is an offset, where m≧0, andK^(m) is the number of available resource indices in the RB_(m), wherem=0, 1, . . . M−1, where M is the number of available RBs for recourseindices, a is a value between 0 and N−1, where N is the number of CCEsfor the UE, and n is the RB index for the UE.

If at least one of the determined resource indices for the UE exceedsthe number of available resource indices in one RB, The apparatus 80 mayfurther include a removing unit 803 and/or a rearranging unit 804.

The removing unit 803 is configured to remove the at least one of thedetermined resource indices.

The rearranging unit 804 is configured to rearrange the position of theCCEs that will be received by the UE to make sure that the resourceindices for the UE are in one RB.

The resource indices are DRS indices or ACK/NACK indices.

The apparatus 80 may further include a first allocating unit 805 and/ora second allocating unit 806.

The first allocating unit 805 is configured to allocate one determinedDRS index for each logical antenna if the UE has multiple logicalantennas.

The second allocating unit 806 is configured to allocate at least twodetermined ACK/NACK indices for one logical antenna.

The apparatus 80 may further include a third allocating unit 807configured to allocate at least one determined ACK/NACK index for onelogical antenna.

The apparatus 80 may be a UE or a base station.

According to the embodiment of the present invention we can see that theapparatus 80 can determine multiple resource indices for a UE implicitlybecause the apparatus 80 maps the CCEs to at least two resource indicesfor the UE according to predetermined mapping rule. The apparatus 80 candetermine at least two resource indices for a UE if the number ofavailable resource indices in each RB is the same, or if the number ofavailable resource indices in the first RB is less than the number ofavailable resource indices in other RBs, or if the number of availableresource indices in each RB is different. The apparatus 80 can avoidsome unavailable resource indices for a UE which exceeds the number ofavailable resource indices in one RB. If the apparatus 80 is a UE, afterallocating one DRS index to each logical antenna, the UE with multiplelogical antennas can transmit uplink data via different logical antenna.This will improve the uplink performance of a UE through transmitdiversity especially when it is a cell edge UE. Furthermore, if theapparatus 80 is a UE, after allocating at least two ACK/NACK indices forone logical antenna, the UE can transmit uplink data through code orspatial multiplexing via the logical antenna. This will increase theuplink information transmission capacity through code or spatialmultiplexing.

One embodiment of the present invention will now be described withreference to FIG. 9 showing a system 90 for determining a resource indexin a wireless communication system, which includes a base station 91 anda UE 92.

The base station 91 is configured to allocate at least two CCEs to theUE 92; map the CCEs to at least two resource indices for the UE 92according to a predetermined mapping rule, and send the CCEs to the UE92.

The UE 92 is configured to receive the CCEs from the base station 91,and map the CCEs to at least two resource indices for the UE 92according to a predetermined mapping rule.

Concretely, as shown in FIG. 10, the base station 91 may include amapping unit 801. The mapping unit 801 is configured to map at least twoCCEs for the UE 92 to at least two resource indices for the UE 92according to a predetermined mapping rule.

The base station 91 may further include an allocating unit 911configured to allocates the at least two CCEs to the UE 92.

The mapping unit 801 may further include at least one following unit: afirst determining unit 8011, a second determining unit 8012, and a thirddetermining unit 8013.

The first determining unit 8011 is configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

mod(s+m,K)+a

where s is the first CCE index of the UE 92, m is an offset, where m≧0,K is the number of available resource indices within one RB, and a is avalue between 0 and N−1, where N is the number of CCEs for the UE 92.

The second determining unit 8012 is configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

$\{ {\begin{matrix}{s + m + a} & {if} & {{s + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {if} & {{s + m} \geq K^{re}}\end{matrix}\quad} $

where s is the first CCE index of the UE 92, m is an offset, where m≧0,a is a value between 0 and N−1, where N is the number of CCEs for the UE92, K^(re) is the number of available resources indices in the first RB,and K is the number of available resources indices within a second RB.

The third determining unit 8013, configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

${s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$

where s is the first CCE index of the UE 92, m is an offset, where m≧0,and K^(m) is the number of available resource indices in the RB_(m),where m=0, 1, . . . M−1, where M is the number of available RBs forrecourse indices, a is a value between 0 and N−1, where N is the numberof CCEs for the UE 92, and n is the RB index for the UE 92.

If at least one of the determined resource indices for the UE 92 exceedsthe number of available resource indices in one RB, The base station 91may further include a removing unit 803 and/or a rearranging unit 804.

The removing unit 803 is configured to remove the at least one of thedetermined resource indices.

The rearranging unit 804 is configured to rearrange the position of theCCEs that will be received by the UE 92 to make sure that the resourceindices for the UE 92 are in one RB.

The resource indices are DRS indices or ACK/NACK indices.

The base station 91 may further include a recording unit 912 which isconfigured to record the resource indices for the UE 92.

The base station 91 may further include a sending unit 913 which isconfigured to send the CCEs to the UE 92 via a downlink control channel.

With reference to FIG. 11, the UE 92 may further include a mapping unit801 is configured to map at least two CCEs for the UE 92 to at least tworesource indices for the UE 92 according to a predetermined mappingrule.

The UE 92 may further include a receiving unit 921 configured toreceives the at least two CCEs from the base station 91.

The mapping unit 801 may further include at least one following unit: afirst determining unit 8011, a second determining unit 8012, and a thirddetermining unit 8013.

The first determining unit 8011 is configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

mod(s+m,K)+a

where s is the first CCE index of the UE 92, m is an offset, where m≧0,K is the number of available resource indices within one RB, and a is avalue between 0 and N−1, where N is the number of CCEs for the UE 92.

The second determining unit 8012 is configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

$\{ {\begin{matrix}{s + m + a} & {if} & {{s + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {if} & {{s + m} \geq K^{re}}\end{matrix}\quad} $

where s is the first CCE index of the UE 92, m is an offset, where m≧0,a is a value between 0 and N−1, where N is the number of CCEs for the UE92, K^(re) is the number of available resources indices in the first RB,and K is the number of available resources indices within a second RB.

The third determining unit 8013, configured to determine at least tworesource indices for the UE 92, and each resource index is determinedaccording to

${s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$

where s is the first CCE index of the UE 92, m is an offset, where m≧0,and K^(m) is the number of available resource indices in the RB_(m),where m=0, 1, . . . M−1, where M is the number of available RBs forresource indices, a is a value between 0 and N−1, where N is the numberof CCEs for the UE 92, and n is the RB index for the UE 92.

If at least one of the determined resource indices for the UE 92 exceedsthe number of available resource indices in one RB, the UE 92 mayfurther include a removing unit 803.

The removing unit 803 is configured to remove the at least one of thedetermined resource indices.

The resource indices are DRS indices or ACK/NACK indices.

The UE 92 may further include a first allocating unit 805 and/or asecond allocating unit 806.

The first allocating unit 805 is configured to allocate one determinedDRS index for each logical antenna if the UE 92 has multiple logicalantennas.

The second allocating unit 806 is configured to allocate at least twodetermined ACK/NACK indices for one logical antenna.

The UE 92 may further include a third allocating unit 807 configured toallocate at least one determined ACK/NACK index for one logical antenna.

According to the embodiment of the present invention we can see that thesystem 90 can determine multiple resource indices for the UE 92implicitly because it maps the CCEs to at least two resource indices forthe UE 92 according to predetermined mapping rule. The system 90 candetermine at least two resource indices for the UE 92 if the number ofavailable resource indices in each RB is the same, or if the number ofavailable resource indices in the first RB is less than the number ofavailable resource indices in other RBs, or if the number of availableresource indices in each RB is different. The system 90 can avoid someunavailable resource indices for the UE 92 which exceeds the number ofavailable resource indices in one RB. If the UE 92 has multiple logicalantennas, after allocating at least two different DRS indices to atleast two different logical antennas, the UE 92 can transmit uplink datavia different logical antenna. This will improve the uplink performanceof the UE 92 through transmit diversity especially when it is a celledge UE. Furthermore, after allocating at least two ACK/NACK indices forone logical antenna, the UE 92 can transmit uplink data through code orspatial multiplexing via the logical antenna. This will increase theuplink information transmission capacity through code or spatialmultiplexing.

Some detailed embodiments are given to make the present inventionclearer.

One detailed embodiment is assumed that every RB used to transmit uplinkinformation has same number of resource indices, c=3 and Δ_(shif)=2, andthe total number of resource indices available within one RB isK=12*3/2=18 according to the formula (4), which is numbered as 0, 1, . .. , 17. In this example, there are five UEs receiving PDCCH from a basestation.

1. The base station allocates a number of CCEs to each UE.

The base station schedules each UE by allocating a particular number ofCCEs in relation to Channel Quality Information and amount of controlinformation to be transmitted in downlink direction for the UE.

The 5 UEs are allocated PDCCH consisting of 1, 1, 2, 4 and 8 CCEs,respectively.

The mapping of CCEs to PDCCH is shown in FIG. 12.

2. The base station maps the CCE to resource index for each UE. If a UEhas more than one CCEs, the base station maps the CCEs to at least tworesource indices for the UE according to a predetermined mapping rule.

If the broadcast offset information m equals 1, every UE has same RBindex 0 according to formula (3). The DRS indices for each UE could bedetermined according to formula (2): Zd1={1}, Zd2={2}, Zd3={3,4},Zd4={5,6,7,8}, Zd5={9,10,11,12,13,14,15,16}.

The ACK/NACK indices for each UE could be determined according toformula (2): Za1={1}, Za2={2}, Za3={3,4}, Za4={5,6,7,8},Za5={9,10,11,12,13,14,15,16}.

In this embodiment, the base station maps all the resource indices foreach UE.

The base station may record the RB index, DRS indices and ACK/NACKindices of each UE.

3. The base station may send the CCEs as showed in FIG. ? to each UE viaa downlink control channel.

4. The UE4 with two logical antennas receives its CCEs for it from thecontrol channel.

5. The UE4 maps its CCEs to at least two resource indices according to apredetermined mapping rule.

The UE4 finds its CCE indices {4, 5, 6, 7} according to the positions ofits CCEs in the CCE sequence.

The UE4 maps its CCE indices to at least two resource indices accordingto a predetermined mapping rule.

Because the broadcast offset information m equals 1, the UE4 candetermine its RB index 0 according to formula (3). It just maps two DRSindices {6, 8} according to formula (2) from a part of its CCE indices{5, 7}, and it determines its 4 ACK/NACK indices {5,6,7,8} according toformula (2).

6. After determining its resource indices, The UE4 uses the RB index,DRS indices and ACK/NACK indices to transmit the uplink information.

It allocates the RB index 0, DRS index 6 and ACK/NACK indices {5,6} tothe first logical antenna; the RB index 0, DRS index 8 and ACK/NACKindices {7,8} to the second logical antenna.

The UE4 can transmit control information to a base station via differentlogical antennas because different logical antennas have a differentdetermined DRS index, and can also transmit data through code or spatialmultiplexing via the logical antenna because one logical antenna has twodetermined ACK/NACK indices.

One detailed embodiment is assumed again that c=3 and Δ_(shift)=2, thetotal number of resource indices within one RB is K=12*3/2=18 accordingto formula (4), which is numbered as 0, 1, . . . , 17. Furthermore thereare two RBs used for PUCCH ACK/ANCK transmission, where the first RBonly has 6 resource indices, so Kre=6, and the second RB has 18 resourceindices. In this example, there are six UEs receiving PDCCH from a basestation.

1. The base station allocates a number of CCEs to each UE.

The base station schedules each UE by allocating a particular number ofCCEs in relation to Channel Quality Information and amount of controlinformation to be transmitted in downlink direction for the UE.

The 6 UEs are allocated PDCCH consisting of 2,2,2,2,4 and 4CCEsrespectively.

The mapping of CCEs to PDCCH is shown in FIG. 13.

2. The base station maps the CCE to resource index for each UE. If a UEhas more than one CCEs, the base station maps the CCEs to at least tworesource indices for the UE according to a predetermined mapping rule.

If the broadcast offset information m equals 0, UE1, UE2, UE3 have sameRB index 0 and UE4, UE5, UE6 have same RB index 1 according to formula(6). The DRS indices for UE1, UE2, UE3, UE4, UE5, UE6 could bedetermined according to formula (5): Zd1={0,1}, Zd2={2,3}, Zd3={4,5},Zd4={0,1}, Zd5={2,3,4,5}, Zd6={6,7,8,9}.

The ACK/NACK indices for each UE could be determined according toformula (5): Za1={0,1}, Za2={2,3}, Za3={4,5}, Za4={0,1}, Za5={2,3,4,5},Za6={6,7,8,9}.

In this embodiment, the base station maps all the resource indices foreach UE.

The base station may record the RB index, DRS indices and ACK/NACKindices of each UE.

3. The base station may send the CCEs as showed in FIG. 13 to each UEvia a downlink control channel.

4. The UE6 with three logical antennas receives its CCEs for it from thecontrol channel.

5. The UE6 maps its CCEs to at least two resource indices according to apredetermined mapping rule.

The UE6 finds its CCE indices {12, 13, 14, 15} according to thepositions of its CCEs in the CCE sequence.

The UE6 maps its CCE indices to at least two resource indices accordingto a predetermined mapping rule.

Because the broadcast offset information m equals 0 and Kre=6, the UE6can determine its RB index 1 according to formula (6). It just maps twoDRS indices {6, 7} according to formula (5) from a part of its CCEindices {12, 13}, and it also just maps two ACK/NACK indices {7, 9}according to formula (5) from a part of its CCE indices {13, 15}.

6. After determining its resource indices, The UE6 uses the RB index,DRS indices and ACK/NACK indices to transmit the uplink information.

It allocates the RB index 1, DRS index 6 and ACK/NACK indices 7 to thesecond logical antenna; the RB index 1, DRS index 7 and ACK/NACK indices9 to the second logical antenna.

The UE4 can transmit control information to a base station via differentlogical antennas because at least two different logical antennas have adifferent determined DRS index.

One detailed embodiment shows a case using the exception, i.e. there isa resource indices allocation problem for one of the UEs. Assume thateach RB used to transmit uplink information has same number of resourceindices, c=3 and Δ_(shift)=3, and the total number of resource indicesavailable within one RB is K=12*3/3=12 according to the formula (4),which is numbered as 0, 1, . . . , 11. In this example, there are fourUEs receiving PDCCH from a base station.

1. The base station allocates a number of CCEs to each UE.

The base station schedules each UE by allocating a particular number ofCCEs in relation to Channel Quality Information and amount of controlinformation to be transmitted in downlink direction for the UE.

The 4 UEs are allocated PDCCH consisting of 2, 2, 4 and 4 CCEsrespectively.

The mapping of CCEs to PDCCH is shown in FIG. 14.

2. The base station maps the CCE to resource index for each UE. If a UEhas more than one CCEs, the base station maps the CCEs to at least tworesource indices for the UE according to a predetermined mapping rule.

If the broadcast offset information m equals 2, every UE has same RBindex 0 according to formula (3). The DRS indices for each UE could bedetermined according to formula (2): Z_(d1)={2,3}, Z_(d2)={4,5},Z_(d3)={6,7,8,9}, Z_(d4)={10,11,12,13}.

The ACK/NACK indices for each UE could be determined according toformula (2): Z_(a1)={2,3}, Z_(a2)={4,5}, Z_(a3)={6,7,8,9},Z_(a4)={10,11,12,13}.

In this embodiment, the base station maps all the resource indices foreach UE.

It can be observed that two DRS {12, 13} allocated for UE4 exceed therange of DRS within one RB (since there are only 12 DRS s). The ACK/NACKindices for UE4 also have this problem.

When this case occurred, the determined DRS for UE4 would be Zd4={10,11}and ACK/NACK indices for UE4 would be Za4={10,11} according to the firstexception solution.

In another way, the base station can rearrange the CCEs for UE4 to avoidthe problem. This is exception solution 2. For example, the mapping ofCCE to PDCCH could be changed to what is shown in FIG. 15,

In this case, the RB index for UE4 would be 1; the DRS determined forUE4 would be Zd4={2,3,4,5}, and the ACK/NACK indices for UE4 would beZa4={2,3,4,5}. The PUCCH for UE4 will be transmitted in the second RB.

The base station may record the RB index, DRS indices and ACK/NACKindices of each UE.

3. The base station may send the CCEs as showed in FIG. ? to each UE viaa downlink control channel.

4. The UE4 with two logical antennas receives its CCEs for it from thecontrol channel.

5. The UE4 maps its CCEs to at least two resource indices according to apredetermined mapping rule.

The UE4 finds its CCE indices {12,13,14,15} according to the positionsof its CCEs in the CCE sequence.

The UE4 maps its CCE indices to at least two resource indices accordingto a predetermined mapping rule.

Because the broadcast offset information m equals 2, the UE4 candetermine its RB index 1 according to formula (3). It just maps threeDRS indices {2,3,5} according to formula (2) from a part of its CCEindices {12,13,15}, and it determines its 4 ACK/NACK indices {2,3,4,5}according to formula (2).

6. After determining its resource indices, The UE4 uses the RB index,DRS indices and ACK/NACK indices to transmit the uplink information.

It allocates the RB index 1, DRS index {2,5} and ACK/NACK indices {4,5}to the first logical antenna; the RB index 1, DRS index 3 and ACK/NACKindices {2,3} to the second logical antenna.

The UE4 can transmit control information to a base station via differentlogical antennas because different logical antennas have a differentdetermined DRS index, and can also transmit data through code or spatialmultiplexing via the logical antenna because one logical antenna has twodetermined ACK/NACK indices.

Embodiments within the scope of the present invention also include acomputer program product with computer program code A1, schematicallyshown in FIG. 16, which, when executed by a computer, will enable thecomputer to perform the steps of the above described inventive method.Specifically, the present invention relates to a computer programproduct with computer program code A1 which, when executed, will enablea base station or a user equipment to perform the steps of the inventivemethod described above. The present invention also relates to a computerreadable medium A for carrying or having computer program code A1according to the invention, such as computer-executable code,computer-executable instructions, computer-readable instructions, ordata structures, stored thereon. Such computer readable medium may beany available medium, which is accessible by a general-purpose orspecial-purpose computer system. By way of example, and not limitation,such computer-readable medium can comprise physical storage media suchas RAM, ROM, or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other media which can be used tocarry or store desired program code means in the form ofcomputer-executable instructions, computer-readable instructions, ordata structures and which may be accessed by a general-purpose orspecial-purpose computer system. FIG. 16 illustrates the computerreadable medium as a compact disc.

The embodiments as well as the features of such embodiments describedabove can be combined if they do not exclude each other.

It will be understood that the invention is not restricted to theaforedescribed and illustrated exemplifying embodiments thereof and thatmodifications can be made within the scope of the inventive concept asillustrated in the accompanying claims.

1. A method for determining a resource index in a wireless communicationsystem, comprising: for at least two control channel elements (CCEs),for a user equipment (UE), mapping the CCEs to at least two resourceindices for the UE according to a predetermined mapping rule.
 2. Themethod according to claim 1, further comprising: establishing the atleast two CCEs for the UE.
 3. The method according to claim 1, whereinthe mapping of the CCEs to at least two resource indices for the UEaccording to a predetermined mapping rule further comprises: determiningat least two resource indices for the UE, wherein each resource index isdetermined according tomod(s+m,K)+a where s is the first CCE index of the UE, m is an offset,where m≧0, K is the number of available resource indices within oneresource block (RB), and a is a value between 0 and N−1, where N is thenumber of CCEs for the UE.
 4. The method according to claim 1, whereinthe mapping of the CCEs to at least two resource indices for the UEaccording to a predetermined mapping rule further comprises: determiningat least two resource indices for the UE, wherein each resource index isdetermined according to $\{ {\begin{matrix}{s + m + a} & {if} & {{s + m} < K^{re}} \\{{{mod}( {{s + m - K^{re}},K} )} + a} & {if} & {{s + m} \geq K^{re}}\end{matrix}\quad} $ where s is the first CCE index of the UE, mis an offset, where m≧0, a is a value between 0 and N−1, where N is thenumber of CCEs for the UE, K^(re) is the number of available resourcesindices in the first RB, and K is the number of available resourcesindices within a second RB.
 5. The method according to claim 1, whereinthe mapping of the CCEs to at least two resource indices for the UEaccording to a predetermined mapping rule further comprises: determiningat least two resource indices for the UE, wherein each resource index isdetermined according to${s + m - {\sum\limits_{m = 0}^{n - 1}K^{m}} + a},{{{where}\mspace{14mu} {\sum\limits_{m = 0}^{n - 1}K^{m}}} < {s + m} \leq {\sum\limits_{m = 0}^{n}K^{m}}}$where s is the first CCE index of the UE, m is an offset, where m≧0, andK^(m) is the number of available resource indices in the RB_(m), wherem=0, 1, . . . M−1, where M is the number of available RBs for resourceindices, a is a value between 0 and N−1, where N is the number of CCEsfor the UE, and n is the RB index for the UE.
 6. The method according toclaim 1, wherein the method further comprises: removing at least one ofthe determined resource indices for the UE when the at least one of thedetermined resource indices for the UE exceeds the number of availableresource indices in one RB.
 7. The method according to claim 1, whereinthe method further comprises: rearranging the position of the CCEs thatwill be received by the UE to make sure that the resource indices forthe UE are in one RB when at least one of the resource indices exceedsthe number of available resource indices in one RB.
 8. The methodaccording to claim 1, wherein the resource indices are demodulationreference signals, DRS, indices or ACK/NACK indices.
 9. The methodaccording to claim 8, wherein the UE has multiple logical antennas, themethod further comprises: allocating, by the UE, one determined DRSindex for each logical antenna.
 10. The method according to claim 9,wherein the method further comprises: allocating at least two determinedACK/NACK indices for one logical antenna.
 11. The method according toclaim 9, wherein the method further comprises: allocating at least onedetermined ACK/NACK index for one logical antenna.
 12. An apparatus fordetermining a resource index in a wireless communication system,comprising: a mapping unit, configured to map at least two controlchannel elements (CCEs) for a user equipment (UE) to at least tworesource indices for the UE according to a predetermined mapping rule.13. The apparatus according to claim 12, wherein the apparatus furthercomprises: an establishing unit, configured to establishing the at leasttwo CCEs for the UE.
 14. The apparatus according to claim 12, whereinthe resource indices are demodulation reference signals, DRS, indices orACK/NACK indices.
 15. The apparatus according to claim 14, wherein ifthe UE has multiple logical antennas, the apparatus further comprises: afirst allocating unit, configured to allocate one determined DRS indexfor each logical antenna.
 16. The apparatus according to claim 15,wherein the apparatus further comprises: a second allocating unit,configured to allocate at least two determined ACK/NACK indices for onelogical antenna.
 17. The apparatus according to claim 15, wherein theapparatus further comprises: a third allocating unit, configured toallocate at least one determined ACK/NACK index for one logical antenna.18. A system for determining a resource index in a wirelesscommunication system, comprising: a base station, configured tocommunicate to a user equipment (UE), allocate at least two controlchannel elements (CCEs) to the UE, and map the CCEs to at least tworesource indices for the UE according to a predetermined mapping rule,and send the CCEs to the UE; wherein the UE is configured to receive theCCEs from the base station, and map the CCEs to at least two resourceindices for the UE according to the predetermined mapping rule.
 19. Acomputer readable medium carrying computer program code, which, whenexecuted, enables a computer to perform the steps of a method accordingto claim
 1. 20. At least one processor configured to perform a method toclaim 1.